Hair was a part of the anatomy that grew all over the body on many creatures and beings, mostly mammalian (like the Klingons and the Orks) and reptomammalians (like the Falleen or some of the Species of the Combined Army) species. Humans, the dominant sentient species in the multiverse grew hair in all manner of places except for the soles of their feet and the palms of their hands. Other species like the Wookiees were fully covered with a thick coat of hair. Hair came in a great variety of thicknesses, lengths and colors, but usually lost its hue with old age. As it was made of a living material, all hair would grow and fall when the cells died. In younger beings, soon after the cells died, new ones grew again in the same place, making new hair. The regrowth process became less efficient with old age however, eventually leading to baldness.